Sunflower secret to more

Transgenic Implants

One kilogram of lupin seed — the product of seven years of research — has allowed CSIRO Plant Industry scientists to plot a course for increased profits for both pulse growers and livestock producers.

The result is a genetic recipe for making lupins a better meal for intensively-fed livestock. The secret ingredient: sunflower gene.

Laboratory rats have shown the good taste to prefer the improved lupin seed which, more importantly, had more than double the amount of methionine, a critical amino acid, found in normal lupin seed.

Lupins, like all other pulses, are deficient in some of the 10 amino acids essential for diets in monogastric animals such as chickens, pigs and humans. Low levels of the sulphurcontaining amino acid methionine result in reduced livestock weight gains, and for this reason lupins are a less than ideal component of some stock feed mixes.

Plant Industry researcher TJ Higgins said that the traditional solution has been to supplement the animals' diet with pure methionine. This gives the right balance of sulphur amino acids, but is an added expense for the producer.

Dr Higgins said the project, supported by growers through the GRDC, aimed to make the lupin plant produce more of its own methionine. "We did this by taking a gene from a sunflower and putting it into the lupin. The gene makes the plant produce a protein that is rich in methionine."

Field trials last Spring at the Centre for Legumes in Mediterranean Agriculture yielded 40 kg of seed. In collaboration with a team of Danish scientists, 1 kg of the genetically altered grain was fed to rats to test its nutritional value, in the first experiment of its kind in the world.

Savings: $7/t

CSIRO has calculated that the genetically improved seed may be worth at least $7/t to livestock producers, simply through the savings on amino acid supplements. Other less direct and quantifiable costs include less fibre downgrading for wool producers using lupins and the fact that improved lupin seed may prove more palatable to livestock.

The next stage is to work with animal nutritionists, said Dr Higgins. A much larger field trial, to be harvested in November, will provide seed for feeding experiments with chickens and sheep.